Adjustable wheelchair handrim with movable friction band

Abstract

An adjustable manual wheelchair handrim with a moveable elastomeric friction band. The position of the tubular handrim can be moved to a desired location relative to the wheel rim depending on the needs and limits of the user. The movable friction band is stretched around the drive surface of the handrim at a desired location preventing it from moving and providing increased frictional properties when gripped by the user during pushes. The friction band can be permanently affixed at a location to further prevent movement and slippage between the handrim and the friction band.

Description

[0001]This application claims benefit of and priority to U.S. Provisional Application No. 61 / 447,989, filed Mar. 1, 2011, by W. Mark Richter, and is entitled to that filing date for priority. The specification, figures and complete disclosure of U.S. Provisional Application No. 61 / 447,989 are incorporated herein by specific reference for all purposes.FIELD OF INVENTION[0002]This invention relates generally to wheelchair handrims and, in particular, to an adjustable wheelchair handrim with a moveable friction band.BACKGROUND OF THE INVENTION[0003]Manual wheelchair users control and propel their wheelchairs with the handrims, also commonly called pushrims, handrings, and handrails. Handrims enable the user to propel forward, turn and brake. Unfortunately, there is a high occurrence of upper extremity injuries as a result of the repetitive stresses experienced by the user when gripping and pushing their handrims.[0004]When propelling forward, the typical wheelchair user reaches back, g...

AI Technical Summary

Benefits of technology

The present invention is a better wheelchair handrim assembly that improves the user's ability to push the wheelchair by reducing slippage and the required gripping force between the user's hand and the handrim. The assembly includes an ergonomically shaped, tubular handrim with a continuous drive surface that spans the gap between the handrim and the wheel rim. The drive surface protects the user's fingers from getting caught and blocks them from jamming into the wheel composition. The assembly also has adjustable offset distance between the wheel rim and the handrim, which allows users to position the handrim at their ideal distance from the tire. This customization will increase propulsion efficiency while reducing strain on the upper extremities of the user. The assembly also features a movable, high friction band that prevents circumferential movement when the user grips and applies a torque to the handrim during pushes. This band can be adjusted in size, shape, and position to provide maximum gripping surface for each individual user. Overall, the present invention enhances the efficiency and comfort of wheelchair handrims.

Problems solved by technology

Unfortunately, there is a high occurrence of upper extremity injuries as a result of the repetitive stresses experienced by the user when gripping and pushing their handrims.

The greater the gripping force, the higher amount of friction between the hands and handrims, and ultimately the greater the deceleration.

Since wheelchair users rely on their upper extremities in this manner, pain and injuries to their arms and shoulders can significantly affect their mobility, and consequently, their independence and quality of life.

Although effective, there are some drawbacks and inconveniences that are inherent with these designs.

One drawback is that these handrims have a limited gripping surface for the user's hand to engage during pushing and breaking.

Another drawback is that the offset between the handrim and the wheel is not adjustable, providing a standard spanning distance for all users regardless of their hand size and gripping limitations.

This makes it impossible for users with smaller hands to use the previously discussed technique of grabbing both the wheel and handrim for climbing hills or starting from rest.

It is also known that the user's fingers can get caught in the area between the wheel and handrim or jammed by the rigid standoffs as the wheel rotates.

Another characteristic of typical handrims is that most are generally made of a smooth metal with poor frictional properties.

This results in the users needing to grip on the rim with considerable force in order to prevent slippage.

While these designs are effective in improving the frictional propertied of the handrim, the coating tends to burn the hand of the user during braking.

While these designs are better than the typical handrim, one problem they possess is that the location of the high friction is permanent.

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